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// Copyright (C) 2018 Valerie Young. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-%asyncfromsynciteratorprototype%.return
description: return() will unwrap a Promise value return by the sync iterator
info: |
%AsyncFromSyncIteratorPrototype%.return ( value )
...
2. Let promiseCapability be ! NewPromiseCapability(%Promise%).
...
5. Let return be GetMethod(syncIterator, "return").
...
17. Let steps be the algorithm steps defined in Async-from-Sync Iterator Value Unwrap Functions.
...
22. Return promiseCapability.[[Promise]].
Async-from-Sync Iterator Value Unwrap Functions
An async-from-sync iterator value unwrap function is an anonymous built-in
function that is used by methods of %AsyncFromSyncIteratorPrototype% when
processing the value field of an IteratorResult object, in order to wait for
its value if it is a promise and re-package the result in a new "unwrapped"
IteratorResult object. Each async iterator value unwrap function has a
[[Done]] internal slot.
flags: [async]
features: [async-iteration]
---*/
var obj = {
[Symbol.iterator]() {
return {
next() {
return { value: 1, done: false };
},
return() {
return {
value: Promise.resolve(42),
done: true
};
}
};
}
};
async function* asyncg() {
yield* obj;
}
let iter = asyncg();
iter.next().then(function (result) {
iter.return().then(
function (result) {
assert.sameValue(result.value, 42, "Result.value should be unwrapped, got: " + result.value);
iter.next().then(({ done, value }) => {
assert.sameValue(done, true, 'the iterator is completed');
assert.sameValue(value, undefined, 'value is undefined');
}).then($DONE, $DONE);
}
).catch($DONE);
}).then($DONE, $DONE);
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